Safety device for elevators



(No Model.)

T. W. HEERMANS.

SAFETY DEVICE FOR ELEVATOES. No. 403,668. Patented May 21,1889.v

li L: lllilllllll UNITED STATES PATENT OEEICE.

THADDEUS WV. HEERMANS, OF CHICAGO, ILLINOIS, ASSIGNOR TO IHE CRANEELEVATOR COMPANY, OF ILLINOIS.

SAFETY DEVICE FOR ELEVATORS.

SPECIFICATION forming part of Letters Patent No. 403,668, dated May 21,1889.

Application filed February 9, 1889. Serial No. 299,241. (No model.)

To all whom, t may concern:

Be it known that I, THADDEUS W. HEER MANS, of Chicago, in the county ofCook and State of Illinois, have invented certain new and usefulImprovements in Elevators, of which the following is a specification.

My invention specially applies to that class of safety devices att-achedto the car or cage in which the catches or pawls are under ordinarycircumstances kept out of action by a retaining pawl or detent, and arereleased and applied when the normal speed of descent of the elevator1is exceeded.

My invention is designed to render the release of the detent certainwhenever the normal speed is exceeded, and, further, to provide againstaccident from the breakage or derangement of the parts.

My invention consists in the parts and combinations hereinafterdescribed and claimed.

In the accompanying drawings, Figure 1 is a side elevation of the uppercross-beam of an elevator car or cage and such portion of the safetydevice as is necessary to illustrate my invention. Fig. 2 is a top viewof the same. Fig. 3 is a side view of the pulley carrying thedetent-tripping weight. Fig. et is a central cross-section of the sameand the stud upon which it turns.

A, Fig. 1, is the upper cross-beam of the elevator car or cage. To thiseross-beam is pivoted a lever, B, which may be tilted by the spring C,connected thereto by a rod, D, whenever the spring C is released. Thespring, rod, and lever may be adapted to operate any of the ordinary andwell-known safety-catches, one form of which is shown in Letters PatentNo. 313,240, of March 3, 1885, to G. H. Reynolds; but as the presentinvention is not concerned therewith the catches are not shown in thedrawings. The detent E, engaging with a stud, F, on the rod D, serves toprevent the action of the spring and the consequent setting of thecatches, except when said detent is moved so as to release the rod D. Apulley, G, is pivoted to the beam A, and a stationary rope, H, extendingup and down the elevator-shaft, passes around a groove in the edge ofthe pulley, and also around the double= grooved pulley I, a rope beingcrossed between the pulleys G and I, so as to have a greater frictionalsurface on the pulley G. As a result of this construction, the pulley Gis caused to revolge Whenever the car moves up or down in the shaft.Pivoted at N to the pulley Gis a weight, J, (shown in dotted outline inFig. 1, and in full lines in Fig. 3, which shows the opposite face ofthe pulley Gfrom that shown in Fig. 1.) The pulley G is recessed inorder to accommodate the weight J, the opposite side of the pulley beingleft thicker, so that the pulley and weight, considered as a whole,shall be balanced. This weight consists of an elongated body, which issomewhat curved in order to bring it within the circumference of thepulley G and in a more favorable position for the action of centrifugalforce upon it. This curved body is recessed, as shown at M in section,Fig. 4, for the reception of a spiral spring, L. The thrust of the outerend of said spring L is received upon a set-screw, k, passing throughthe flange g of the pulley G. The weight J is also provided with atongue, y', the outer end of which, as shown, projects slightly beyondthe circumference of the pulley G. The tongue j is in the same plane )asthe arm e of the detent E. (Vide Fig. 2.

The mechanism which the release of the detent puts in operation may beconnected with a friction-brake, with a signal-bell, with theoperating-valve of the engine, or with any lof the operating orregulating parts or attach ments of the engine or elevator.

The operation of the device is as follows: As the safety-catches areonly intended to protect the too sudden descent of the cage, the devicefor tripping the detentand allow-V ing the catch-setting devices tooperate is only calculated to come into use upon the descent of thecage, in which case the revolution of the pulley G is in the directionindicated by the arrow thereon. (Vide Fig. 1.) When revolving in thisdirection, the free end of the weight J is in advance, and when inposition to release the detent E the force of gravitation isco-operating with the centrifugal force to oppose the tension of thespring L. The face of the arm e of the detent E which comes in contactwith the projection j is approximately normal to the line joining thepoint of contact and the pivot N, (vide Fig. 1,) on Which the Weight Jturns. The result is that incase the centrifugal force becomes greatenough to bring the Weight J at all into contact With the arm e of thedetent' E the releasing of the detent is mechanically certain, and doesnot depend at all upon the centrifugal force of the Weight J, for thefriction between the surfaces of the projection .j and the arm e,combined with the advancing motion of the pulley G, causes the Weight Jto swing on its pivot end and thereby throw the projecting tongue jstill farther outward.

and as a further result, if the spring L should become relaxed or shouldbe broken, it could not pass unnoticed, because gravitation would Ycause the weight J to swing out from the pulley and to come in Contactwith the again c, and would then necessarily release the detent withoutthe aid of any centrifugal force or mo- As, a result, the release of thed'etent E is assured,

advanced free end being adapted to make' contact with said detent when anormal speed of descent is exceeded, substantially as de scribed.

THADDEUS XV. HEERMANS.

hWitnesses:

P. H. T. MASON, O. R. BARNETT.

